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COVID-19 and its impact on society have raised concerns about scaling up mechanical ventilation (MV) systems and the energy consequences. This paper attempted to combine MV and portable air cleaners (PACs) to achieve acceptable indoor air quality (IAQ) and energy reduction in two scenarios: regular operation and mitigating the spread of respiratory infectious diseases (RIDs). We proposed a multi-objective optimization method that combined the NSGA-II and TOPSIS techniques to determine the total equivalent ventilation rate of the MV-PAC system in both scenarios. The concentrations of PM2.5 and CO2 were primary indicators for IAQ. The modified Wells-Riley equation was adopted to predict RID transmissions. An open office with an MV-PAC system was used to demonstrate the method’s applicability. Meanwhile,a field study was conducted to validate the method and evaluate occupants’ perceptions of the MV-PAC system. Results showed that optimal solutions of the combined system can be obtained based on various IAQ requirements,seasons,outdoor conditions,etc. For regular operation,PACs were generally prioritized to maintain IAQ while reducing energy consumption even when outdoor PM2.5 concentration was high. MV can remain constant or be reduced at low occupancies. In RID scenarios,it is possible to mitigate transmissions when the quanta were < 48 h−1. No significant difference was found in the subjective perception of the MV and PACs. Moreover,the effects of infiltration on the optimal solution can be substantial. Nonetheless,our results suggested that an MV-PAC system can replace the MV system for offices for daily use and RID mitigation.


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Multi-objective optimization of mechanical ventilation with the aid of purifiers in two scenarios: Regular operation and mitigating the spread of respiratory infectious diseases

Show Author's information Yiqun Li1Yujie Fan2Chengqiang Zhi1Wei Ye1,3( )Xu Zhang1
School of Mechanical Engineering, Tongji University, Shanghai 201804, China
Department of Building Science, Tsinghua University, Beijing 100084, China
Key Laboratory of Engineering Structure Performance Evolution and Control, Ministry of Education, Tongji University, Shanghai 200092, China

Abstract

COVID-19 and its impact on society have raised concerns about scaling up mechanical ventilation (MV) systems and the energy consequences. This paper attempted to combine MV and portable air cleaners (PACs) to achieve acceptable indoor air quality (IAQ) and energy reduction in two scenarios: regular operation and mitigating the spread of respiratory infectious diseases (RIDs). We proposed a multi-objective optimization method that combined the NSGA-II and TOPSIS techniques to determine the total equivalent ventilation rate of the MV-PAC system in both scenarios. The concentrations of PM2.5 and CO2 were primary indicators for IAQ. The modified Wells-Riley equation was adopted to predict RID transmissions. An open office with an MV-PAC system was used to demonstrate the method’s applicability. Meanwhile,a field study was conducted to validate the method and evaluate occupants’ perceptions of the MV-PAC system. Results showed that optimal solutions of the combined system can be obtained based on various IAQ requirements,seasons,outdoor conditions,etc. For regular operation,PACs were generally prioritized to maintain IAQ while reducing energy consumption even when outdoor PM2.5 concentration was high. MV can remain constant or be reduced at low occupancies. In RID scenarios,it is possible to mitigate transmissions when the quanta were < 48 h−1. No significant difference was found in the subjective perception of the MV and PACs. Moreover,the effects of infiltration on the optimal solution can be substantial. Nonetheless,our results suggested that an MV-PAC system can replace the MV system for offices for daily use and RID mitigation.

Keywords: infiltration, multi-objective, mechanical ventilation, portable air cleaners, open office

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Publication history
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Acknowledgements

Publication history

Received: 30 October 2022
Revised: 12 January 2023
Accepted: 02 February 2023
Published: 25 April 2023
Issue date: May 2023

Copyright

© Tsinghua University Press 2022

Acknowledgements

Acknowledgements

The China National Key R&D Program partially supported this project during the 13th Five-year Plan Period (No. 2017YFC0702700). In addition, the authors would like to thank the guidance and the IEA EBC Annex 78 project participants, especially Dr. Pawel Wargocki, for valuable discussions and advice on this study.

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